濒危植物——长喙毛茛泽泻的雌雄配子体发育

长喙毛茛泽泻 Ranalisma rostratum stapf 小孢子母细胞的减数分裂过程为连续型,四分体为左右对称型。成熟花粉为三胞花粉。花药绒毡层为变形绒毡层。雌蕊由多数单室子房构成,每子房中含一具双珠被、薄珠心的倒生胚珠。胚囊发育为葱型。成熟胚囊中三个反足细胞退化;二个极核分别位于中央细胞的两端,其体积相差明显。这种极核分布可能与反足细胞过早退化有关。     

不同生境内濒危植物长喙毛茛泽泻种群数量动态比较

湖南茶陵自然种群动态在一年内表现为春季数量下降，以后振荡变化。在以莼菜为主的样方中，种群在夏季以后一直呈增加趋势，至冬季末数量下降；在杂草拥挤的样方内，种群基本呈下降趋势。湖北武汉，网室中迁地保护的种群生长在理想条件下，单一种群呈逻辑斯缔（Ｌｏｇｉｓｔｉｃ）增长，方程为Ｎ（株／ｍ２）＝８４０１＋ｅ４．４７７－０．２６４ｔ。江西东乡回归原产地的种群在回归当年经过精心照顾，种群呈增加趋势，次年随着杂草茂盛生长，种群数量迅速下降，种群具消失的危险。长喙毛茛泽泻种群数量的变动很大程度上受水位变化和杂草干扰的影响。实验结果表明，长喙毛茛泽泻种群能成功地实施迁地保护。     

长喙毛茛泽泻的花器官发生

用扫描电镜对长喙毛茛泽泻的花器官发生进行了观察。该种的花器官发生在泽泻科中既典型又比较特殊。其特殊之处在于从花原基的发生直至最外轮６枚雄蕊原基的发生过程存在单向发育：３个萼片和原基和３个花瓣原基的发生存在次序性,萼片原基和花瓣原基均为顺时针发生,邻近花序侧生分支复合芽的萼片原基和花瓣原基倾向于优先发生;     

濒危植物——长喙毛茛泽泻的受精作用及胚和胚乳的发育

长喙毛茛泽泻Ranalisma rostratum Stapf的配子融合开始较早,但精核与极核融合速度较快。精核与珠孔极核融合后即移向胚囊合点端与另一极核再融合形成初生胚乳核。初生胚乳核第一次分裂后形成两个细胞,以后珠孔端胚乳细胞再进行游离核分裂,胚乳发育属于沼生目型。开花后两天,合子分裂,八分体呈4层,每层呈两个细胞方式排列胚胎发生属于石竹型。     

长喙毛茛泽泻（泽泻科）的交配系统研究

对濒凶植物长喙毛茛泽泻的交配系统作了综合研究。结果理：该种的花粉粒和柱头较平滑,花内分泌细胞存在但欠发达,开花前花粉萌发率较高而开花１ｈ后花粉萌发能力急剧衰退,花粉／胚珠比较低,花部综合特征与其花前期闭花授粉的交配习性相适应。该种的自然居群及实验居群中均未观察到花间的虫媒传粉,仅有极小型昆虫起花内传粉作用,亦未检出风媒花粉流。     

长喙毛茛泽泻胚中营养物质的积累与消耗

长喙毛茛泽泻是一种水生濒危植物。它的种子中没有胚乳,营养物质以淀粉和帽白体的形式贮藏在胚中。胚不同部位物质积累情况差异较大,下胚轴和子地细胞中的淀粉,蛋白体数目多,体积大,胚芽和胚根分生细胞中只贮藏有少量的淀粉粒和蛋白体。     

迁地保护中普通野生稻和长喙毛茛泽泻种群动态及评价

通过对江西东乡含濒危植物普通野生稻（Ｏｒｙｚａｒｕｆｉｐｏｇｏｎ）和长喙毛茛泽泻（Ｒａｎａｌｉｓｍａｒｏｓｔｒａ－ｔｕｍ）的群落在余江县实施重建,研究并评价了迁地保护后的濒危植物种群动态。结果表明,普通野生稻种群呈迅速增长的趋势,分布面积迅速扩大,有性繁殖正常,实生苗补充在种群增长中起重要作用;无性繁殖旺盛,对新生境表现出良好的适应性。在两年实验研究期间,长喙毛茛泽泻种群数量和分布面积迅速扩大,在良好生境中通过有效扩散使种群占据塘底有利生境,并通过无性繁殖及短暂有性繁殖实现种群更新。两个濒危种迁地保护是成功的,杂草是阻碍两个濒危植物种群增长的主要原因,水位控制是实验塘生境管理的重要手段。     

长喙毛茛泽泻和冠果草种子贮藏及萌发特性（简报）

开花后30d的长喙毛茛泽泻种子生活力较高，60d起急剧下降；冠果草种子生活力明显高于长喙毛茛泽泻。两类种子均宜水浸贮藏。于贮后的长喙毛茛泽泻种子不能萌发，而冠果草种子仍有较高的萌发率。     

长喙毛茛泽泻的种群分布格局和群落内种间关联

长喙毛茛泽泻茶陵种群呈斑块分布,格局类型为聚集分布型,每个亚种群也呈聚集分布,但聚集强度不同。长喙毛茛泽泻与其几个主要伴生种的相关性经测定结果是：与莼菜及黄花狸藻之间的相关性不显著;与柳叶箬、双穗雀稗及石龙尾之间正相关显著;与疏勿蓼之间负相关显著,长喙毛茛泽泻种子近距离传播以及无性繁殖特性是造成其聚集分布的主要原因。柳叶箬、双穗雀稗和石龙尾对长喙毛茛泽泻具有极强的竞争作用。     

长喙毛茛泽泻遗传多样性及其与繁育系统的关系

利用聚丙烯酰胺凝胶电泳技术测定了濒危植物长喙毛茛泽泻（ＲａｎａｌｉｓｍａｒｏｓｔｒａｔｕｍＳｔａｐｆ）及３个对照种冠果草［Ｓａｇｉｔａｒｉａｇｕａｙａｎｅｎｓｉｓｓｓｐｌａｐｐｕｌａ（ＤＤｏｎ）Ｂｏｇｉｎ］、武夷慈姑（ＳｗｕｙｉｅｎｓｉｓＪＫＣｈｅｎｅｔａｌ）、矮慈姑（ＳｐｙｇｍａｅａＭｉｑ）共６个自然居群的遗传多样性。自花受精和以营养繁殖为主的长喙毛茛泽泻维持较低的遗传多样性,预期杂合度和观察杂合度分别为００６４和０１０４。以自花受精为主的冠果草遗传多样性更低,预期杂合度和观察杂合度分别为００３９和００６７。异体繁育但以营养繁殖为主的武夷慈姑遗传多样性比长喙毛茛泽泻的高,预期杂合度和观察杂合度分别为０１１１和０１８３。以异体繁育为主和营养繁殖的矮慈姑遗传多样性在这４个种中最高,其预期杂合度和观察杂合度分别是０１５５和０２６９。４个种的内繁育系数Ｆ值全为负值。冠果草、长喙毛茛泽泻、武夷慈姑直至矮慈姑,其异交程度从几乎为零逐渐递增,而其遗传多样性指标也相应地增高。长喙毛茛泽泻的遗传多样性程度高于冠果草但冠果草并不濒危,因此遗传多样性较低并不是濒危的直接原因     

Life history traits and parental care in Lepilemur ruficaudatus

In this study we investigated the importance of biparental care for the evolution and/or maintenance of pair-living in red-tailed sportive lemurs (Lepilemur ruficaudatus), a nocturnal folivorous lemur. Between 2000 and 2005, we collected data on life history traits from a total of 14 radio-collared pairs of adults and their offspring in Kirindy forest, western Madagascar. Predation rate varied between years with a minimum of 0% and a maximum of 40% per year. Patterns of parental care were quantified during simultaneous focal observations of both pair-partners in 2003 and 2004. Mating activity was limited to the months of May and June, as indicated by conspicuous changes of vulval morphology and male mate guarding behavior. After a gestation length of about 5 months, which is much longer than expected for a lemur of this body mass, single infants were born in November. Lactation lasted for about 50 days. Apart from lactation, females provided infant care by warming, grooming and transporting infants orally. Infants were parked in dense vegetation while females foraged. Males were seen only rarely in proximity to infants and we found no evidence for direct infant care provided by social fathers. We conclude that the necessity of direct infant care cannot explain the evolution and/or maintenance of pair-living in Lepilemur ruficaudatus.     

Life history traits of the tropical freshwater copepod Mesocyclops longisetus (Crustacea: Copepoda)

The life history traits of a tropical copepod population of Mesocyclops longisetus were measured in the laboratory under defined and controlled culture conditions. Egg duration times at 25 and 30 °C were 42.1 and 29.6 hours, respectively. Development times from nauplius I to adult females and males were 22.3 and 18.3 days, respectively. Body sizes (cephalothorax length) of adult females and males were 1.00 and 0.60 mm, respectively. Clutch size averaged 70.2 eggs. Comparison of these traits with those of its congeners reveals considerable life history variation in the genus Mesocyclops. Lipid analyses of early stage eggs showed that the percent composition of triglycerides to total lipid in M. longisetus (22%) is similar to that of Mesocyclops edax (17%) and daphniid cladocerans, but only half that of a marine calanoid copepod. We suggest that zooplankton may adapt to different resource environments by either adjusting their egg size or altering the proportion of lipid that is readily available for metabolic energy of embryos and nauplii. The diverse arrays of zooplankton life histories may be explained in part by adaptations in lipid metabolism in response to the level and predictability of resources.     

Life history traits and abundance can predict local colonisation and extinction rates of freshwater mussels

1. A critical need in conservation biology is to determine which species are most vulnerable to extinction. Freshwater mussels (Bivalvia: Unionacea) are one of the most imperilled faunal groups globally. Freshwater mussel larvae are ectoparasites on fish and depend on the movement of their hosts to maintain connectivity among local populations in a metapopulation. 2. I calculated local colonisation and extinction rates for 16 mussel species from 14 local populations in the Red River drainage of Oklahoma and Texas, U.S. I used general linear models and AIC comparisons to determine which mussel life history traits best predicted local colonisation and extinction rates. 3. Traits related to larval dispersal ability (host infection mode, whether a mussel species was a host generalist or specialist) were the best predictors of local colonisation. 4. Traits related to local population size (regional abundance, time spent brooding) were the best predictors of local extinction. The group of fish species used as hosts by mussels also predicted local extinction and was probably related to habitat fragmentation and host dispersal abilities. 5. Overall, local extinction rates exceeded local colonisation rates, indicating that local populations are becoming increasingly isolated and suffering an ‘extinction debt’. This study demonstrates that analysis of species traits can be used to predict local colonisation and extinction patterns and provide insight into the long‐term persistence of populations.     

Life history traits, maternal behavior and infant development of blue-eyed black lemurs (Eulemur flavifrons)

An understanding of recruitment is important for estimating population growth and viability, and their implications for conservation. We present the first results regarding the life history, maternal behavior and infant development of the critically endangered blue-eyed black lemur (Eulemur flavifrons) of Madagascar. The species breeds seasonally, with births occurring at the end of the dry season, between late August and October. Over two successive birth seasons in 2006 and 2007, we observed a total of 13 lactating females and 22 infants from six groups. We inferred age at first reproduction as 3 years, and calculated the birth rate as 1.0 infant per female per year with a mean inter-birth interval of 358 ± 24.81 days (319-410 days). Infants spent the first 3 weeks of life constantly with their mothers; locomotor independence and ingestion of solid food began at week 10, and the infants were weaned by week 25. After week 28, infants spent less than 20% of their time in contact with their mothers. Over the study period infant mortality was 22.7%, with predation and sickness observed as causes. Our results suggest that overall recruitment is relatively slow, which has implications for the species' survival, particularly given their restricted and threatened habitat.     

Life history of a lacustrine ostracod

The ostracod Cypria turneri has one generation per year in Mirror Lake, New Hampshire. Juveniles hatch in January through May and reach maturity by August. The life history of this ostracod suggests that the turnover rate of the population is low.     

Life history,ecology and longevity in bats

The evolutionary theory of aging predicts that life span should decrease in response to the amount of mortality caused by extrinsic sources. Using this prediction, we selected six life history and ecological factors to use in a comparative analysis of longevity among 64 bat species. On average, the maximum recorded life span of a bat is 3.5 times greater than a non-flying placental mammal of similar size. Records of individuals surviving more than 30 years in the wild now exist for five species. Univariate and multivariate analyses of species data, as well as of phylogenetically independent contrasts obtained using a supertree of Chiroptera, reveal that bat life span significantly increases with hibernation, body mass and occasional cave use, but decreases with reproductive rate and is not influenced by diet, colony size or the source of the record. These results are largely consistent with extrinsic mortality risk acting as a determinant of bat longevity. Nevertheless, the strong association between life span and both reproductive rate and hibernation also suggests that bat longevity is strongly influenced by seasonal allocation of non-renewable resources to reproduction. We speculate that hibernation may provide a natural example of caloric restriction, which is known to increase longevity in other mammals.